Yesterday, Matt has mentioned the "conscious breathing", explaining how this can be useful if our mind is not able to handle the "disappointment." I have done the necessary research, and I landed in the mysterious depths of Yoga practice (mysterious to me that I never practiced anything like that). Control the breathing means using "prana" in a correct way, to the point that we can get rid of any block. Use breathing properly removes the blocks, which are a consequence of forced interruption of the breath flow. [...]

We live these interruptions throughout our life path. In the web I read about a very simple example: the baby immediately begins to use the breath in a natural way, without pause, and he does this when he laughs, when he cries, when he interacts with other people. Later, with the growth, the child experiences feelings and emotions that are not innate, such as "fear", and this feeling creates in him interruptions in his normal breath flow. A practice to learn how use properly our breathing in a conscious way is called Prāṇāyāma.

The Prāṇāyāma (rhythmic control of the breath) is the fourth stage of yoga, which, along with Pratyahara (withdrawal of the mind from the objects of senses), is known as the inner search (Antaranga sadhana). They teach you how to control your breathing and mind, as a means of freeing the senses from the slavery of the objects of desire. Prāṇāyāma is a Sanskrit word meaning "extension of the prāṇa or breath" or more accurately, "extension of the life force". The word is composed to Prāṇa, life force, or vital energy, particularly, the breath, and "ayāma", to extend or draw out. (Not 'restrain, or control' as is often incorrectly translated from 'yama' instead of 'ayāma'). Thomas McEvilley translates prāṇā as "spirit-energy". Its most subtle material form is the breath, but is also to be found in blood, and its most concentrated form is semen in men and vaginal fluid in women. Ramamurti Mishra says that: “Expansion of individual energy into cosmic energy is called prāṇāyāma (prāṇa, energy + ayām, expansion).” The Patanjali indicates pranayama as one of eight ways to reach union with the Paramatma (God, the first unit). These techniques allow precisely the union of body, mind and soul with God:

1- Yama

2- Niyama

3- Asana

4- Pranayama

5- Pratyahara

6- Dharana

7- Dhyana

8- Samadhi

Pranayama should be practiced every day and after a quiet practice of "asanas" (yoga postures which are used to reach a state of maxium peacefulness). The best time to practice pranayama is early morning (before dawn) and after sunset. It is recommended to practice at least 15 minutes per day, and about regularly, at the same time, place, position, sitting on the floor, on a small pillow or folded blanket, keeping your back straight. You will have to keep your eyes closed, otherwise the mind will ease to become distracted by external objects. The uniformity of breathing makes the mind serene and calm. After you have finished practice, it is recommended to lie down in Shavasana position (or Savasana, the Corpse Pose) for at least 5 to 10 minutes, in complete silence and relaxation, to refresh both body and mind.

I recommend that before you start trying any form of control of breathing, to seek as much information as possible and maybe read some books about it.